The work proposed falls into two categories: a proposed multicenter trial to validate a newly developed surgical technique, selective lymph node dissection (SLND) and studies, utilizing information and pathological tissues from melanoma patients attending the Clinic at the John Wayne Cancer Institute, to develop criteria to separate individuals with a good or bad prognosis. In the first project we will teach the pathology skills necessary to perform and distribute the necessary reagents for the immunohistochemistry studies. We will act as consultants and trouble shooters during the trial and convene periodic meetings of pathologists to ascertain quality assurance and review difficult cases. We will collate the data that are generated and prepare any resulting publications. In the second block of studies we will examine histologic preparations from melanoma patients seen at JWCI and UCLA according to a multifactorial protocol and undertake immunohistochemical examinations of primary melanoma to ascertain and quantify the extent of their presence. Such factors will include dendritic leukocytes of skin, lymph and lymphoid tissues, vascularity, lymphoid infiltration, and secondary epidermal hyperplasia. All the above factors will be analyzed singly and in combination for their association with a favorable or unfavorable clinical outcome. From this we expect to develop a multifactorial prognostic score that will predict outcome for the individual patient. We will also extend our studies of the occurrence and distribution of occult tumor cells by seeking such cells in the blood and bone marrow and relate these cells detected in different tissue compartment to clinical outcome.